Self-cleaning filter



Dec. 16, 1952 T. R. SMITH SELFcLEAN1NG FILTER 2 SHEETS-SHEET l Filed Dec. 13, 1947 INVENTOR, BY CYoma/A @dwf/L /y' l. ITZRITIEY.

Dec. 16, 1952 T. R. SMITH 2,621,797

SELF-CLEANING FILTER Filed Deo. 15, 1947 2 SHEETS-SHEET 2 y INVENTOR. BY Uomfw QmL// ATTORNEY.

Patentedl Dec. 16, 1952 SELF-CLEANING FILTER Thomas R. Smith, Newton, Iowa, assignor to Maytag Company, Newton, Iowa, a corporation of Delaware Application December 13, 1947, Serial No. 791,483

(Cl. Zlib- 152) 'l Claims.

This invention relates to filters for liquids, more particularly to filters of the self-cleaning type and it has for an object to provide improved apparatus of the character set forth.

In clothes Washing machines, especially the type wherein a portion of the Washing liquid continuously ows from the receptacle in which fabrics are washed and is recirculated backV to the washing receptacle, it is desirable to prevent or retard the return of foreign matter or particles such as, for example, heavy dirt, sand, lint, etc.

carried from the receptacle by the liquid, because it is more or less detrimental to the cleaning operation to keep returning the separated dirt and solid matter thereto.` Also, it is desirable to provide means for disposing of the filtered foreign particles at predetermined intervals.

It is therefore another object of the invention to provide a filter which retards the flow of foreign matter and is periodically actuated to release the retarded foreign matter.

It is still another object of the invention to provide a filter for a recir-culating type automatic washing machine which retards the iiow of heavy and large foreign particles back to the cleaning compartment and is periodically actuated by a condition in the cycle of washing to permit the retarded foreign matter to flow to drain.

It is another object of the invention to provide a lter which has self-cleaning characteristics.

It is another object of the invention to provide a filter with a plurality of filaments having small spaces therebetween disposed so that liquid ows thereacross in a tortuous manner whereby foreign particles flowing with the liquid are retarded and retained.

It is yet another object of the invention to provide a filter in a container which is so disposed as to be moved away from an outlet opening when the liquid in the container exceeds a predetermined level.

It is still another object of the invention to provide a self-cleaning lter in a discharge opening which acts to retard foreign particles from flowing therethrough during certain periods and to automatically move to a second position to permit iiow of foreign particles during certain other periods and at the same time be positioned to permit self-cleaning thereof.

It is another object of the invention to providey a filter about an outlet opening to retard flow of foreign particles lin one position and to release the foreign particles in a second position which at the same time is positioned to resist vortcal flow through the outlet opening.

These and other objects are affected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawings, forming a part of this application, in which:

Figure 1 is a diagrammatic partial vertical sectional view of a washing machine of an automatic type having liquid recirculation features vand with the improved filter applied thereto.

Figure 2 is an enlarged vertical sectional view of the improved filter shown in Figure 1 in its raised position.

Figure 3 is a bottom plan view of the filter shown in Figures 1 and 2, and,

Figure 4 is a vertical sectional view of the improved lter with a modied form of actuating means therefor.

Referring now to the drawing for a brief description of one form of apparatus to which the invention may be applied there is shown in Figure l a stationary cylindrical tub or container 9 having a bottom I0 and an access opening Il at the top. Substantially centrally located in the bottom portion of the tub is an annular upstanding open ended column i2 to provide a reservoir or storage space I3 for washing liquids between the column and side wall of the container and an opening through which a hollow shaft or sleeve I=4 extends into the container. This hollow shaft is adapted to support and rotate a movable tub or receptacle l5, having an imperforate bottom I6 and an upwardly extending side wall l'l, in the upper portion of the container and to permit relative motion therebetween. The upper portion of the receptacle l5 has an access opening I8 in alignment with the opening Il in the container and a plurality of overflow openings I9 disposed on a horizontal plane in its side wall which define a washing fluid or liquid level 20 therein. It is obvious that should the level of liquid 20 tend to rise above the openings I9, it will flow out of the openings and fall into the lower portion of the stationary tub 9.

Mounted in the receptacle is an agitator 2i, of any suitable type, which is oscillated or actuated by means of a shaft 22 concentric with and journaled in the hollow shaft i4. Both of these shafts are operatively connected to a motion transmitting mechanism of any suitable type, such as that generally indicated at 23. As this particular mechanism forms no part of the invention, further descriptien is not deemed necessary other than to point sut that the inner shaft 22 is preferably actuated in such mannen as to agitate the fabrics and washing liquid and the hollow shaft I4 is preferably rotated in a single direction to rotate the receptacle at relatively high speed. The means for selectively actuating the shaft 22 or rotating the shaft I4 is preferably under control of a shifting mechanism generally indicated 24 and which includes a solenoid 24a. A pulley 25 disposed on the input side of the transmitting mechanism 23 is driven by means of a belt 26 and a driving pulley 21 rigidly secured to a shaft 28 on a drive motor 29.

Water or washing liquid is admitted through a vertical conduit 3D having its upper end disposed so as to discharge water therefrom directly into the receptacle I5. A solenoid operated constant temperature valve 3| attached to the conduit 39 controls the mixture of hot and cold water from any suitable source 32, in a manner to be hereinafter described Disposed in the bottom I of the stationary container 9 is an integral frusto-conical wall or dished portion 34 forming part of a discharge or outlet opening 35. This opening leads to the inlet of a centrifugal pump 36 driven by a pulley` 31 operatively connected to the drive motor 29 by means of a driving pulley 38 and a belt 39. 'The discharge side of the pump leads to a chamber 40 communicating with a recirculating conduit 4| and a drain conduit 42. A doubleV acting valve 43 operated by means of a lever 44 connected to a solenoid 45 is utilized to direct the flow of washing liquid either to the recirculating conduit 4| disposed to discharge into the rotatable receptacle I5 or to the drain conduit 42.y

which discharges the liquid to the usual sewerage system. With the valve in the position shown, any liquid discharged by the pump 36 flows into the chamber 4 0 and through the recirculation conduit 4I back into the receptacle I5.

Also mounted adjacent the bottom It! is a switch operating iioat 46 pivoted at 41 to actuate a lever 48 carrying a pair of contacts 49 and 5|. The contacts 5I and. 49 are utilized to energize the solenoid valve 3| and driving motor 29, respectively, and act in series with a sequential controlling or timing means 52, This timing means causes the washing apparatus to perform a series of operations in a predetermined sequence and is driven by means of a timer motor 53 and it is also subject to manual adjustment or selection through a control knob 54. As the particular means for causing the apparatus to perform various functions, the drive and manual adjustment therefore may be of any suitable type and as other apparatus may be substituted for that shown and described, further detailed description is not deemed necessary. Also, any suitable iioat and oat operated switch may be utilized instead of the particular type shown.

Referring now to the means for filtering the washing liquid there is shown, in Figures l, 2 and 3, a displaceable filtering means or element 51 disposed about the outlet passage 35 at the bottom I9 of the stationary container 9. The filter element, in this embodiment, preferably comprises a plurality of rows of closely spaced downwardly projecting filaments or bristles 59 mounted in annular U-shaped channels 59a of varying diameters rigidly secured to the lower portion of a stepped substantially frusto-conical movable base member or structure 66 which conforms generally, although not necessarily, to the conical portion 34 at the bottom of the tub. It is to be understood that the particular manner of securing the bristles to the base 69 is not too impor-y tant in that any suitable means may be utilized. The opposite or free ends 6I of the filaments facing in the direction of the outlet opening 35 are trimmed or cut to conform to and rest on or abut the frusto-conical wall portion 34 about the outlet opening 35. It can be seen from the drawings that when the edges of the downwardly projecting filaments are in engagement with the frustoconical wall portion 34 a space or passageway 62 is provided between the portion 34 of the tub and the base portion 59 on the filter element through which washing liquid flows. Thus foreign particles tending to flow to the outlet opening 35 are restricted or retarded by the closely spaced filaments as the water flows therearound and heavy particles are retained therein.

A float or air chamber 63 capable of moving or lifting the filter 51 away from the outlet opening 35 is preferably formed as part of the iilter element and comprises the base 6! secured to a top wall lt4 at its outer diameter and both of these elements are united by an elongated guide tube 65 at the central portion. This air chamber or float acts to raise and lowerthe filter element in accordance with the quantity of washing liquid in the bottom of the stationary tub lil;

In order to insure the proper positioning of the filter element 51 as it is raised and lowered by the liquid accumulated in the' tub there is provided a guide rod or member 66 estending loosely through the annular tube 65 and downward toward the Outlet 35. The' upper end of the guide rod is rigidly fastened by bolts 61, or any other suitable means, to the bracket 68 secured to the stationary tub I0. A stop or shoulder 69 formed or positioned on the guide rod 66 limits the upward travel of the filter element when the lower portion of the tub is filled with water above a predetermined level. This shoulder 69 is so positioned as to permit an unrestricted annular space 'I0 between the conical portion 34 of the drain and the free ends 6| of the filaments during the time when the iioat is raised but at the same time is sufiiciently close so that foreign particles adhering to the downwardly projecting bristles are vigorously acted on by the water flowing to the drain to disengage a large portion of the foreign particles. Also, with the filter in its retracted position vortical movement of the water in its passage downwardly through the outlet opening is resisted and consequently a more rapid emptying of fthe tub is accomplished. y

The utility of this filter element 51 will be apparent from the following brief description of the operation of the machine. The operator places the detergent and fabrics to be washed in the rotary receptacle I5 and thereafter turns the control knob 54 to its desired starting position. Although fthe control dial is positioned the switch operated float 46 is in its downward position to thereby de-energize the rmain drive kand control circuits while the contact 5| is closed. This acts to energize the solenoid valve 3| to permit water to flow through the conduit 35 'from the source 32H and be discharged into the receptacle. When the level of liquid in the receptacle reaches the openings I9 the water overflows and collects in the bottom of the stationary tub I0.

Due to the fact that the stationary tub is empty the filter element willbe positioned against the conical portion 34 of the outlet opening by means of gravity5 As the level in the stationary tub rises to a predetermined level A which is normally slightly below' the point where the float chamber 63 would lift the iilter element 51 away to deenergize or cut off the flow of Water to the yreceptacle and at the same time energize the drive motor 29 and timer motor 53 through contact'49. Thedrive motor rotates the drivenpulley 25 at the drive mechanism 23 which causes the shaft 22 to oscillate the agitator 2i to -thereby Wash the clothing or fabrics.

As the drive motor 23 rotates the pump 36 it withdraws the Washing liquid through the lter element 51 and discharges the :ltered washing fluid into the chamber 43. During the washing operation the double acting Valve 43 is inthe position shown wherein the drain passage 42 is closed and the liquid flows through the recirculating conduit 4I and is discharged back into the receptacle. Thus it can be seen that during the washing operation ltered washing liquid is continuously Withdrawn from the bottom ofthe tub I by the pump and is discharged back into the receptacle I and fthe washing liquid above the normal liquid level 2i) flows out of the overflow openings I9 and falls to the bottom of the tub l0. This washing liquid carries with it heavy dirt and foreign particles and these are carried toward -the drain opening. As the Water flows through the lter in a tortuous path the closely spaced bristles restrict the flow therethrough and at the same time retard and hold a large portion of the foreign particles.

After a predetermined time interval the timer motor 53 advances the timing means 52 which completes a circuit through solenoid 45 which is actuated to shut off the recirculating conduit 4I and to open the chamber 40 to the drain conduit 42. The advancement of the timing means 52 also completes a circuit through the solenoid 24a to operate the shifting mechanism 24 for disconnecting the shaft 22 from its driving relation with the motor 23 and to cause an operative driving relation between the motor 25 and the sleeve I4 to thereby rotate the receptacle I5 at high speed in one direction. When the receptacle is rotated at high speed, the washing liquid is rapidly thrown or expelled from the tub through the openings I3 and accumulates in the bottom of the stationary tub. The space between the bottom of the tub and the top of the annular column I2 is preferably of such capacity as to hold at least the entire contents of the Washing liquid in the rotary receptacle I5. During the initial portion of the spin period the flow of water from the receptacle I5 is at a much greater rate than can be removed by the pump 36, therefore the water level rises therein to approximately the level B. As the water level rises above a predetermined level, determined by the position and size of the float, the float chamber 63 on the filter element 51 rises with the level and causes the free ends of the filaments on the conical lter element to be with-- ydrawn from the conical surface 34, the distance of withdrawal being determined by the shoulder 63 von the guide rod 66. At this time it can be seen that a large portion of the liquid is permitted to oW directly to the drain. Also, due to the spacing between the bottom edges 6I of fthe filter element and the bottom of the tub, a portion of the liquid iiow is about the filaments in Asubstantially parallel relation thereto and acts to wash away a major portion of the foreign particles adhering thereto which are pumped to drain along with the washing liquid.

Another advantage of limiting the upward displacement of the lter element 51 with respect fto its seat 34 is that vertical movement of the wa'- -ter in its passage downwardly through the outlet opening 35 is resisted wth a resultant effect of permitting a larger quantityof water to flow through the outlet opening in a givenperiod of time. Y

The lter element 51 will remain in its retracted or uppermost position against the shoulderr69 until the liquid level in the stationary tub drops below a predetermined level, after whichthe lter elementunder the influence of gravity will be moved downwardly in guided relation to the rod 66 into its proper filtering position in contact with the seat 34.

Should the openings between the laments of the filter element for any reason become clogged or restricted materially, the Water level will raise in the stationary tub and this in turnwill raise the filter element 51 slightly away from the drain opening to permt the proper flow of liquid for recirculation. Under this condition, filtering would not take place, but the returning of washing liquid to the receptacle is not impaired.

At the end of the spinning operation the solenoid 45 is deenergized which causes the double acting valve 43 to move to its drain shut-off position and the solenoid valve 3| to open to permit rinse water to be admitted to the receptacle. The sequence of operation for rinsing and spinning is similar to that for Washing and spinning.

Referring now to the modification as shown in Figure 4, there is provided a positive means for actuating the lter element 51. This means includes a solenoid 1I acting on a lever 12 pivoted at 13 which provides a guide means for holding the ilter element 51 in a substantially vertical positionabove the outlet opening 35. The 0pposite end of the lever remote from the solenoid is connected to a link 14 secured to the filter element. The solenoid in this instance is controlled by the timer element 52 and is energized to lift the filter element during the period when the receptacle I5 is rotated. Thus it can be seen that during the washing operation the lter element is disposed against the conical portion 34 of the tub by means of gravity and a' spring 15 to retard foreign particles and when the solenoid 1I is energized the lter element 51 is moved away from the drain opening 35 tov permit' the foreign particles to be pumped to drain and at the same time clean the individual laments in the filter element. When the solenoid is energized and seats it provides a suitable stop means for limiting the vertical movement of the lter element away from the seat.

Because the lter is formed of filaments which are all open on the bottom or lower portion and as the flow to the outlet has an angular component with respect to the length of the individual filaments, when the float raises the laments away from the conical surface the collected dirt will be washed from the filaments through the open portion of the lter element and down the drain. j

In the prefer-red form the filter is automatic in operation to the extent that no Vspecial control need be added, because the water level in the bottom of the tub I0 causes the lter to rise and the increased flow, due to the lter being outer the main path of flow, plus the higher water level with a resultant increased pressure, combinesto effectively wash the collected dirt oithe lter element. In the modcation (Figure 4) the r11.e ter is identical except that it is operated by the timer.

From the foregoing it can be seen that a lter dement has peep previded which karte te ,retfpr mellow or foreign particles during certain peredslepd et other periods it acts te permit the discharge of foreign particles to drain. Although this lter element has been disclosed in'conjunction with a recirculating type automatic washing machine it may be applied equally as well to other types of apparatus in which it is desirable to have intermittent filtering,

While the inventionv has been shown in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modicatioIlS without departing from the spirit thereof, and it is desired, therefore, that only such limitations shall be placed thereupon ,as ere ,Specifically eet .fprth in the appended claims.

It is claimed:

1. In combination, a container having a bottom wall with outlet means therein and adapted to have varying quantities of liquid supplied thereto, a lter element comprising a buoyant support, a plurality of substantially co-axial adjacently arranged generally vertical ltering units each of which comprises a body of adjacently disposed elongated laments secured at their upper ends to said support, s aid outlet means including a seat engaged by the lower free ends o f said laments whereby said filtering element is eiective in filtering liquid in said container up to a predetermined level, said iltering .element being vertically displaceable from said seat Aby said buoyant support when said predetermined liquid level is exceeded whereby unltered liquid is discharged through said outlet means. and vertical guide means for said dis.- placeable lter element.

2,. The combination according to claim l, wherein the lter seat is formed with a frustof conical surface and the free ends of the laments .are adapted to be disposed in abutting relation over a substantial portion of said frustorconical surface.

3, In combination, a container having ,a bottom wall with voutlet means therein and adapted to have varying quantities of liquid supplied thereto, a lter element comprising a buoyant support, a plurality of substantially co-axial .adjacently arranged generally vertical vriltering units each of which comprises a body o f adjacently disposed elongated laments secured at their upper ends to said support, said ,outlet means including a seat engaged by -the Alower free ends of said filaments whereby said vfiltering element Yis effective in iltering liquid in said container up to a predetermined level, said 4iiltering element being vertically displaceable from said seat by said `buoyant support when saidpredetermined liquid llevel is exceeded' whereby uniilteredr liquid is discharged through said outlet means, vertical guide means for said displaceable lter element, and stop means for limiting the displacement of said filter .element with respect .to said outlet means.

.4. In Combination, a container ,having a bottom weil with outlet :pearls therein .and adapted toy have varying quantities of liquid Supplied thereto, a lter element comprising ,a buoyant support formed with an air-tight chamber having la, vertical axially disposed guide-way extending therethrough, a plurality of lsubstantially coaxial adjacently arranged filtering units each of which comprises a -body of adjacently disposed elongated iilaments secured at their upper ends to saidk support, said outlet means including a seat fermed with e Heere-eenige ,Seriate epgaged by the lower free ends oi said iilaments whereby said ltering element is effective in iiltering liquid in said container up to a predetermined level, said filtering element being displaceable vertically from said seat by said buoyant support when said predetermined liquid level is exceeded whereby unfiltered liquid is discharged through said outlet means, a guide rod disposed in said guide-way for maintaining said lter element in alignment with said outlet means, and a stop carried by said guide rod for limiting the displacement of said lter element with respect to said outlet means.

5. In a filter, the combination of a lter element and a container for receiving a variable quantity of liquid, said lter element comprising a base member and a plurality of elongated closely spaced generally vertical thin bristle elements having their upper ends secured to said base member to provide a barrier for removal of solid material to be separated by said lter, said container having an opening with a surrounding seat against which the lower opposite ends of the bristle elements abut, a guide member for restricting said ltering element to substantially vertical movement above said opening, and a stop for limiting the vertical movement of said filtering element with respect to said opening whereby the flow of liquid about and through said bristles in the direction of the opening eifects cleaning thereof.

6. In a iilter, the combination of liquid retaining means for receiving variable quantities of liquid and including a bottom wall having a liquid outlet provided with an adjacently disposed frusto-conical seat surrounding said outlet, a lter element including a base member and an annular body of elongated closely spaced generally vertical thin bristle elements, said bristle elements having their upper ends secured to said base member and their lower ends abutting said seat about said opening whereby foreign material in the liquid is retained by said bristle elements during flow through said opening, a guide member for maintaining the lter Velement in a vertical position and for restricting the same to substantially vertical movement above said opening, means for displacing said bristle elements vertically with respect to said seat and outlet opening during a cleaning operation to free the lower ends of said bristles, a'stop for limiting the vertical `movement of said lter element with respect to said seat whereby the liquid owing through and about said bristle elements toward said opening removes the foreign material therefrom.

7. In a filter, the combination of a container for receiving variable quantities of liquid and includin-g av bottom wall having a liquid outlet with a surrounding seat, a iilter element including a base member and a plurality of elongated close -ly spaced generally vertical thin bristle elements, said bristle elements having their upper ends secured to said base member and their lower ends abutting said seat to provide va barrier for removal of solid material in the liquid during flow through said opening, a guide member for fmain- Ataining said lter element in a vertical position and for restricting the same to substantially vertical movement above said openingLand an electro-magnetic operating device operatively connectedv to said filter element for vperiodically displacing the same with respect to .said seat to permit unltered liquid' to flow through said out- 9 I let opening and, whereby the flow' of iiquid Number Name bate through and about said bristles in the direction 1,497,921 Levedahl June 17, 1924 of the opening eects cleaning thereof. 1,521,989 Bergstrom Jan. 6, 1925 THOMAS R. SMITH. 1,874,475 Ellingham Aug. 30, 1932 5 2,298,096 Dunham Oct. 6, 1942 REFERENCES CITED 2,430,078 Reinsch et a1. Nov. 4, 1947 The following references are of record in the 2,439,535 Wilson Apr 13 1948 fue of this patent: 2,449,634 Baade Sept. 21, 1948 UNITED STATES PATENTS 10 2,468,354 Abbrecht Apr. 26, 1949 Number Name Date FOREIGN PATENTS 687,979 Chambers Dec. 3. 1901 Number Country Date 1,108,079 Morrison Aug. 18, 1914 233 Great Britain Jan.5,1897 

